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When to Plant Pac Choi in Snohomish County, WA

Snohomish County, Washington Zone 8b May

May in the garden — Snohomish County, Washington

May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Snohomish County, Washington.

Avg. last frost March 25
Avg. first frost November 2
Soil temp (4") 70°F
Watering High
Pest pressure High
Daylight 15 hrs
  1. Start harvesting pac choi

    The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.

Looking ahead to June
  • First harvests: pac choi

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Pac choi (baby bok choy) is a compact variety of Chinese cabbage with tender leaves and crisp stems. It grows quickly and is ideal for containers and small spaces.

Snohomish County, Washington is in USDA Zone 8b. The average last spring frost is March 25 and the first fall frost is November 2, giving you a growing season of approximately 222 days.

At an elevation of 230 feet, Snohomish County receives approximately 50.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90°F, providing good warmth for Pac Choi during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Pac Choi root diseases.

Snohomish County, WA (Zone 8b) Long season
222 days
Last Spring Frost March 25
222 growing days
First Fall Frost November 2
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Snohomish County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (153 days to spare)
Start indoors: Feb 12 Transplant: Mar 19 🍅 Harvest: Apr 30 – May 28
Recommended (50%) ✓ Fits season (152 days to spare)
Start indoors: Feb 18 Transplant: Mar 25 🍅 Harvest: May 6 – Jun 3
Safe Start (90%) ✓ Fits season (151 days to spare)
Start indoors: Mar 14 Transplant: Apr 18 🍅 Harvest: May 30 – Jun 27

Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.

Soil Compatibility in Snohomish County

How your county's soil matches Pac Choi's growing requirements.

Soil pH

Your soil pH (5.7–6.8) overlaps with Pac Choi's range (6.0–7.5), though not a perfect match.

Soil Texture

The silt loam soil in Snohomish County is excellent for Pac Choi — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (5.4%) — Pac Choi will thrive.

How to Plant Pac Choi

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Pac Choi

6
successive plantings in your 222-day season

Sow every 4.6 weeks. Last sowing by Sep 08 to harvest before frost.

For a dedicated fall crop, sow by Aug 24.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
1.0″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 1,072 gal / 100 sq ft

Monthly Watering Guide for Pac Choi

Pac Choi needs approximately 1.5 inches of water per week (6.5" per month). Here's how your county's rainfall compares month by month.

Month Pac Choi Needs Rainfall You Supplement Action
Jan 7.7" 0" ❄️ Dormant
Feb 5.6" 0" ❄️ Dormant
Mar 6.5" 5" 1.5" 💧 Light watering
Apr 6.5" 3.6" 2.9" 💧 Light watering
May 6.5" 2.6" 3.9" 🚿 Regular watering
Jun 6.5" 1.6" 4.9" 🚿 Regular watering
Jul 6.5" 0.7" 5.8" 🚿 Regular watering
Aug 6.5" 1" 5.5" 🚿 Regular watering
Sep 6.5" 2" 4.5" 🚿 Regular watering
Oct 6.5" 4.2" 2.3" 💧 Light watering
Nov 6.5" 8" 0" ✅ Rainfall sufficient
Dec 8.5" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Snohomish County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Pac Choi Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Pac Choi needs ~831 GDD — county provides 3,885 GDD Excellent fit

Pac Choi Planting Timeline — Snohomish County, WA

Pac Choi Planting Calendar

Activity When Date Range
Start Indoors February 18 Feb 18 – Mar 4
Transplant Outdoors March 25 Mar 25 – Apr 8
Direct Sow March 11 Mar 11 – Apr 1
Harvest May 6 May 6 – Jun 3
Fall Sowing August 24 Aug 24 – Sep 7

Plant 1" deep · 15" apart · Rows 24" apart

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March Start Indoors Transplant Outdoors Direct Sow
April Transplant Outdoors Direct Sow
May Harvest
June Harvest
July
August Fall Sowing
September Fall Sowing
October
November
December
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Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1.5"/week · 1-2 times/week

📅 Days to Maturity

40–55 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 8b

📆 Growing Season

222 days in Snohomish County

Growing Tips for Pac Choi in Snohomish County

Direct sow Pac Choi outdoors after March 25 in Snohomish County when soil has warmed and frost danger has passed.

Your generous 222.0-day season in Snohomish County allows multiple plantings of Pac Choi. Sow every 20.0 days for continuous harvest.

Common pests for Pac Choi in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow in spring or fall. Grows best in cool weather. Space 6 inches apart for baby pac choi. Harvest whole plants or cut outer leaves as needed.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Pac Choi in Snohomish County, WA?

Snohomish County is in Zone 8b with an average last frost of March 25. Plan your Pac Choi planting based on this frost date — see the calendar above for exact timing.

What planting zone is Snohomish County, WA?

Snohomish County, Washington is in USDA Hardiness Zone 8b. The average last spring frost is March 25 and first fall frost is November 2.

🌱

Your Snohomish County Garden Planner — Free

A 24-page printable planner built for Snohomish County (Zone 8b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Snohomish County, WA. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.